A New Perspective on Electrochemistry at The ITIES - Combining μITIES and Confocal Microscopy Using a Gelled Organic Phase in a Glass Membrane

Ion transfer voltammetry using arrays of micro-interfaces between two immiscible electrolyte solutions (μITIES) has emerged as a promising tool for analysis of environmental samples. Here we show that using a gelled organic phase, we can combine μITIES electrochemistry with ex situ techniques, such as confocal fluorescence microscopy. By investigating the transfer of the ionized fluorophore fluorescein, we can use fluorescence confocal microscopy to evaluate the distribution of ions in the organic phase after transfer. We show that the concentration of the fluorophore close to the ITIES after transfer using a constant applied potential is substantially higher than in the aqueous phase, even after a short transfer period. This demonstrates that the use of a high-viscosity organic phase is very promising for analysis and also allows for the combination of ITIES electrochemistry with an array of ex situ measurement techniques.